Liquid‐Phase Growth of Small Crystals for Seeding α‐SiAlON Ceramics

Abstract

Single‐phase small crystals of Li‐, Mg‐, Ca‐, Y‐, Nd‐, and Yb‐α‐SiAlONs have been obtained by liquid‐phase sintering for various compositions and processing conditions. These crystals are suitable for seeding grain growth in α‐SiAlON ceramics. The influence of chemical and processing parameters (starting composition and powders, green density, liquid content, heating schedule, nitrogen pressure, and temperature) on the size and morphology of seed crystals has been investigated. The results are compared with those for β‐Si3N4 crystal formation, and the differences are discussed in terms of nucleation and growth kinetics during liquid‐phase sintering.

Effect of Y‐α‐Sialon Seeding and Holding Time on the Formation of Elongated (Ca,Dy)‐α‐Sialon Crystals Prepared via Carbothermal Reduction and Nitridation

“…in Ref. ), which is well‐ known as a general phenomenon in the crystal/grain growth of various materials, such as α‐Sialon, β‐Sialon, Si 3 N 4 , zeolite . The growth of those crystals/grains mostly occurs in the stage of Oswald ripening with a remarkable feature of coarsening kinetics: larger crystals/grains grow at the expense of smaller ones.…”

Non‐Oxide Ceramics: Structure, Technology, and Applications

“…Sialon powders produced by one of the techniques discussed above can be shaped by slip casting and subsequently consolidated to a fully dense state by HIPing, or by pressureless sintering in the presence of sintering aids such as yttria, sometimes under addition of seed crystals of β -or α -sialon (Zenotchkine et al , 2004 ).…”

Solid-state NMR and XRD study of α-SiAlON powders prepared by combustion synthesis

“…␤-SiAlON is the solid solution of ␤-Si 3 N 4 with Si and N atoms partially substituted by Al and O atoms, arriving at a composition of Si 6−z Al z O z N 8−z (0 < z < 4.2) [1,2]. ␣-SiAlON is derived from ␣-Si 3 N 4 , where For preparing ␣-SiAlON ceramics or powders, several different methods have been reported such as reaction sintering, carbothermal reduction and combustion synthesis [12][13][14]. As a self-sustained reaction process, combustion synthesis seems to be a low-cost technique with much lower energy consumption than other methods and has great potential for large-scale industrial fabrication.…”